Decalcomania and method of using same



Jan. 5, 1960 F. w. HUMPHNER ,009.

DECALCOMANIA AND METHOD OF USING SAME Filed March 25, 1955 SIZED PAPERS/ZED PAPER -('-POLVETHYLENE L P-RECE/V/NG SURFACE INK IMPRINT -HEATEDIRON SIZED PAPER 4JEPOLVETHVLENE RECEIVING SURFACE //w( IMPRINT F 4REMOWBLE $1250 PAPER fl 9' I l I I HP0LrrHrLA/ I RECEIVING SURFACE INKIMPRINT RECEIl ING $UR54CE --POLYETH)*LENE INK IMPRINT IN VEN TOR."

ATZURNEYS.

2,920,009 Patented Jan. 5, 1960 due DECALCOMANIA AND METHQD OF USENGSAME Ferdinand W. Humphner, River Forest, ilk, assignor, by

mesne assignments, to Minnesota Mining and Manufacturing Company, St.Paul, Minn, a corporation of Delaware Application March 23, 1955,flerial No. 496,297

14 Claims. (til. 1'5495) This invention relates to decalcomanias, andmore particularly to a heat-responsive decalcomania and to the methodfor transferring an imprint upon a surface.

Decalcomanias are widely known as a means for accurately transferringprinted letters, figures and other symbols and designs upon a variety ofsurfaces, and are especially suitable where the symbol to be transferredis intricate and detailed. While it would therefore seem thatdecalcomanias or decals are appropriate for the transfer of revenuestamps upon cigarette packages, beverage bottles and similar objects, ithas become apparent that other factors make the present decalcomaniasunsatisfactory for such purposes. The inadequacy of present decals forthese uses results mainly from the fact that the usual decals, afilxedby either heat-responsive or soluble adhesives, may be removed for reuseeither by reapplying heat or by dissolving the particular adhesivematerial.

Therefore, one of the main objects of this invention is to provide adecalcomania adapted to transfer symbols and designs to a given surfacein such a manner that the symbols or designs cannot be removed intactfrom the surface for subsequent reuse. Another object is to provide adecalcomania adapted to be secured to a given surface by a blanketingfilm of an ink-repelling or resisting substance, such as polyethylene. Afurther object is to provide a method for transferring a symbol ordesign, which has been imprinted upon a polyethylene film, to areceiving surface. A still further object is to provide aheat-responsive dccalcomania which is adapted to adhere to smooth,non-porous substances such as cellophane.

Additional objects will appear from the specification and drawings, inwhich- Figure 1 is a side elevation of a decalcomania embodying myinvention; Figure 2 is a side elevation of the same decalcornania incontact with a receiving surface; Figure 3 is a similar side elevationshowing a heated iron being applied to the paper backing upon which thedecalcomania is mounted; Figure 4 illustrates in side elevation theremoval of the paper backing and the transfer of the decalcomania to areceiving surface; and Figure 5 is a top view of tax stamps and serialnumber imprints sealed upon a receiving surface by a protective coatingof polyethylene.

While polyethylene has many properties which make it commerciallydesirable as :a packaging medium for a great number of materials andobjects, it also has the distinctive and heretofore undesirablecharacteristic of repelling or resisting ink, glue and other adhesivesubstances. Considerable difficulty has been caused by this unusualink-resisting property, since identification marks and manufacturerssymbols cannot be printed upon polyethylene surfaces in the customarymanner.

I have discovered, however, that the ink-repelling property ofpolyethylene makes this material particularly suitable for use inconnection with decalcomanias, and especially heat-responsivedecalcomanias. Since the ink will not adhere firmly to a polyethylenesurface, an imprint ing or release sheet,

upon a receiving surface which is covered by a coating of polyethylenecannot be removed by reheating and removing the polyethylene film. Anyattempt to soften or dissolve the polyethylene covering will producedistcrtion or destruction of the ink imprint and will render the inkimpression unsuitable for subsequent use.

In preparing a decalcomania embodying this invention, I first select agrade of sized paper suitable for printing, such as bond paper, bookpaper, coated paper, kraft paper, colored sulphite paper or the like.Any paper which provides a surface satisfactory for printing purposesmay be used.

To the selected paper I then apply an even coating of polyethylene bymeans of a gravure roll or by any other suitable means. As illustratedin Figure 1, the polyethylene does not penetrate the sized paper butinstead forms a separate thermoplastic layer. If a gravure roll is usedto apply the polyethylene, small air bubbles approaching miscroscopicsize may be formed in the polyethylene film. These bubbles assume apattern resembling the design upon the gravure roll, thus impartingmarks of identification upon the polyethylene-coated paper. In order toprevent the formation of larger bubbles, a defoaming agent may be used.Defoaming agents are well known and readily available in the art, andneed not be described in detail here.

The polyethylene may be blended with other substances, such as paraffinand micro-crystalline waxes, which act as extenders for reducing thecosts of the polyethylene coatingwithout materially affecting thedesirable characteristics of the film and its formation.

To the polyethylene-coated paper 1 next apply an ink imprint, as shownin Figure 1. While I prefer to emloy an ink having a high resin varnishcontent combined with added synthetic resins, such as phenolic and alkydresins, other inks having different constituents may be used to producesatisfactory results. As a result of the unique properties ofpolyethylene, ink will not firmly anchor upon or penetrate into thepolyethylene film, but will be Weakly held on the films surface so thatsubequent transfer of the imprint may be simply and effectivelyaccomplished as will be described presently.

To transfer the ink imprint, I first bring the inkimprinted polyethyleneagainst a surface of cellophane, paper, glass or other material, asshown in Figure 2.. The polyethylene is then softened by the applicationof heat whichmay be furnished by a heated iron, as in Figure 3, or byany other suitable heating unit. The heated polyethylene becomes a fluidmass which flows over the ink imprint and seals it upon the coolerreceiving surface. Figure 4 shows the removal of the sized paperbackleaving the ink imprint upon the transfer surface under a protectivefilm of polyethylene.

it should be apparent from the fore oing that polyethylene, unlike theadhesives generally used in connection with decalcomanias, does notserve as a carrier for transferring the ink imprint to the receivingsurface, since the polyethylene passes into a fluid or semi-liquid stateupon the application of heat to the paper backing upon which theimprinted polyethylene is affixed. The weak forces retaining the imprintupon the polyethylene are broken upon heating so that the polyethyleneflows freely and allows the imprint to transfer to the cooler surfaceWithout distortion.

Where a complete transfer of polyethylene from the sized paper releasesheet to a receiving surface is desired, I have found that polyethylenehaving a loW molecular weight produces the most satisfactory results.The phrase low molecular Weight is here used to mean polyethylene havinga molecular Weight within the range of 4,000 to 12,900. In particular, Ihave found that where polyethylene having 'a molecular weight of 7,000is heated to a temperature of about 100 C. by the application of aheating unit to the back of the polyethylene-coated release sheet, asubstantially complete transfer of the polyethylene to a receivingsurface results. It is apparent, however, that the particulartemperature used to obtain proper transfer of the resin ink and thepolyethylene may be varied depending upon the weight of the paperrelease sheet and the temperature of the receiving surface.

There may be instances, however, where a separate transfer of an inkimprint upon a transfer surface is desired without the accompanyingtransfer of polyethylene. In such a case, polyethylene having a highmolecular weight in the range of 12,000 to 16,000 may be used to producea satisfactory transfer of the resin ink imprint without the attendingformation of a protective polyethylene seal.

When the polyethylene-coated release sheet is heated to a temperature atwhich the resin imprint becomes tacky enough for attaching to areceiving sheet, high molecular weight polyethylene does not reach astage of viscosity and tackiness for flowing upon and adhering to areceiving sheet. Upon the removal of the heating element from the backof the release sheet, the high molecular Weight polyethylene quicklyreturns to a solid state and remains as a film upon the sized paperrelease sheet.

Thus, where high molecular weight polyethylene is used, all, or nearlyall, of the polyethylene remains upon the sized paper backing and onlythe ink imprint is transferred. I have found that this result is mostsatisfactorily obtained Where the temperatures are in the range of ll02C., although it is again evident that temperatures outside of this rangemay be used, according to the nature of the sized paper release sheetand the temperature of the receiving surface.

While I have spoken of the ink-repelling properties of polyethylene, itis to be understood that I refer to polyethylene which has not undergonespecial treatment to overcome this unique characteristic. It isnecessary that the polyethylene used in conjunction with this inventionhas the characteristic ink-repelling or resisting properties which havebeen heretofore considered undesirable.

The decalcomania of the present invention is particularly useful foraffixing openwork imprints, such as the tax stamp imprint illustrated inFigure 5, since the imprint cannot be removed and reapplied intact.Frequently, tax stamps are accompanied by serial numbers which haveheretofore been applied to receiving surfaces as part of the stampitself, so that removal of the stamp would also result in removal of theserial number. A particular advantage of my polyethylene decalcomania isthat a serial number imprint may be transferred to a receiving surfaceat the same time but independent from the transfer of a tax stampimprint upon the same surface and so that the serial number and stampimprints are a spaced distance from each other upon the receivingsurface. Thus, two adjacent imprints may be independently andsimultaneously affixed to a receiving surface and sealed upon thatsurface by a single protecting film of polyethylene.

While I have described the decalcomania product and the steps of mytransfer process in considerable detail, it will be apparent to thoseskilled in the art that these details may be varied widely withoutdeparting from the spirit of this invention.

I claim:

1. A heat-responsive decalcomania comprising a sized paper backing, afilm of polyethylene material upon said paper backing, and an inkimprint having substantially no tensile strength and being disposed uponthe exposed surface of said film in direct surface contact therewith.

2. A decalcomania comprising a sized paper release sheet, a film ofpolyethylene material having one surface thereof in contact with saidsheet and having a molecular weight no greater than 12,000, and an inkimprint having substantially no tensile strength and being disposed uponthe opposite surface of said polyethylene film in direct surface contacttherewith.

3. A decalcomania comprising a sized paper backing sheet, a film ofpolyethylene material having one surface thereof in contact with saidsheet and having a molecular weight greater than 12,000, and an inkimprint having substantially no tensile strength and being disposed uponthe opposite surface of said polyethylene film in direct surface contacttherewith.

4. A decalcomania comprising a sized paper release sheet, a film uponsaid release sheet of polyethylene material comprising a blend ofpolyethylene and microcrystalline waxes, and an ink imprint havingsubstantially no tensile strength and being disposed upon the exposedsurface of said film in direct surface contact therewith.

5. A decalcomania comprising a sized paper release sheet, a film uponsaid release sheet of polyethylene material comprising a blend ofpolyethylene and paraflin, and an ink imprint having substantially notensile strength and being disposed upon said film of polyethylene andparafiin in direct surface contact therewith.

6. A heat-responsive decalcomania comprising a backing sheet, a film ofpolyethylene material having one surface thereof in contact with saidbacking sheet, and an ink imprint having substantially no tensilestrength and being disposed upon the opposite exposed surface of saidfilm in direct surface contact therewith.

7. The heat-responsive decalcomania of claim 6 in which said filmconsists of unblended polyethylene.

8. A heat-responsive decalcomania comprising a sized paper, a layer oversaid sized paper of polyethylene material having a molecular weight nogreater than 12,000 and being releasable in semi-liquid condition fromsaid sized paper upon the application of heat, and an ink imprint havingsubstantially no tensile strength and being disposed directly upon theexposed surface of said layer of polyethylene material, whereby, uponthe application of heat to said decalcomania, said layer passes into asemi-liquid condition and said semi-liquid polyethylene material andsaid ink imprint are adapted to be simultaneously heat released andtransferred together upon a receiving surface so that upon cooling saidpolyethylene material forms a protective seal over the transferredimprint upon 'said receiving surface.

9. The method of affixing an ink imprint upon a receiving surfacecomprising the steps of coating a sheet of sized paper with a film ofpolyethylene material, imprinting directly upon the exposed surface ofsaid film, placing a receiving surface in direct contact with theexposed and imprinted surface of said film, heating said film until saidpolyethylene material reaches a semifluid state, and removing the sheetof sized paper from the imprinted receiving surface.

10. The method of afiixing an ink imprint upon a receiving surfacecomprising the steps of coating a sheet of sized paper with a film ofpolyethylene material having a molecular Weight greater than 12,000,imprinting directly upon the exposed surface of said polyethylene filmwith an openwork ink imprint, placing a receiving surface in directcontact with said openwork ink imprint, softening said polyethylene filmto a semi-fluid state by the application of heat, and simultaneouslyremoving the sheet of sized paper and said polyethylene film from saidreceiving surface to leave said imprint thereon.

11. The method of transferring an imprint upon a receiving surface andcovering said imprint with a film of polyethylene, comprising the stepsof covering a sheet of sized paper with a layer of polyethylene having amolecular weight no greater than 12,000, applying an imprint upon theexposed surface of said polyethylene layer, placing a receiving surfacein contact with said imprinted and exposed surface of said polyethylenelayer, softening said polyethylene layer to a semi-fluid stateReferences Cited in the file of this patent UNITED STATES PATENTSMarksberry Aug. 26, 1947 Wittgren July 3, 1951 Wittgren July 3, 1951Rathke Dec. 11, 1951 Rathke Feb. 24, 1953 Hoover Aug. 16, 1955 HooverOct. 25, 1955 Matthes May 22, 1956

1. A HEAT-RESPONSIVE DECALCOMANIA COMPRISING A SIZED PAPER BACKING, AFLIM OF POLYETHYLENE MATERIAL UPON SAID PAPER BACKING, AND AN INKIMPRINT HAVING SUBSTANTIALLY NO TENSILE STRENGTH AND BEING DISPOSED UPONTHE EXPOSED SURFACE OF SAID FLIM IN DIRECT SURFACE CONTACT THEREWITH. 9.THE METHOD OF AFFIXING AN INK IMPRINT UPON A RECEIVING SURFACECOMPRISING THE STEPS OF COATING A SHEET OF SIZED PAPER WITH A FLIM OFPOLYETHYLENE MATERIAL IMPRINTING DIRECTLY UPON THE EXPOSED SURFACE OFSAID FLIM, PLACING A RECEIVING SURFACE IN DIRECT CONTACT WITH THEEXPOSED AND IMPRINTED SURFACE OF SAID FLIM, HEATING SAID FLIM UNTIL SAIDPOLYETYLENE MATERIAL REACHES A SEMIFLUID STATE, AND REMOVING THE SHEETOF SIZED PAPER FROM THE IMPRINTED RECEIVING SURFACE.